1. Field of the Invention
The present invention relates to agricultural implements, and, more particularly, to agricultural tillage implements with shank assemblies.
2. Description of the Related Art
Farmers utilize a wide variety of tillage implements to prepare soil for planting. Tillage implements prepare the soil by way of mechanical agitation of numerous types, such as digging, stirring, and overturning. Examples of tillage include plowing (overturning with moldboards or chiseling with chisel shanks), disking, harrowing, sweeping, and cultivating with cultivator shanks. Tillage implements are often classified into two types: vertical or horizontal tillage. Generally, vertical tillage is performed with implements such as colters or spider wheels. Horizontal tillage, on the other hand, is performed with implements such as sweeps. The employment of vertical and/or horizontal tillage depends upon various aspects of a given situation including soil conditions, equipment, crops to be planted, etc.
Some tillage implements may include two or more sections coupled together to perform multiple functions as they are pulled through fields by an agricultural vehicle. For example, a field cultivator is capable of simultaneously tilling soil and leveling the tilled soil in preparation for planting. Field cultivators convert compacted soil into a level seedbed with a consistent depth for providing optimal conditions for planting of a crop. Residual crop material, weeds, or other undesired plants disposed on top of the soil are destroyed and worked into the soil.
A typical field cultivator generally includes a frame that carries a number of ground-engaging tillage tools for working the soil. For example, shank assemblies with sweeps may be incorporated to create a level seedbed to facilitate optimal seed growth. Some field cultivators may include rear auxiliary tools to perform various secondary tasks for finishing the soil. For example, a rear auxiliary tool may be in the form of a spike tooth harrow, spring tooth harrow, rolling (aka. crumbler) basket, etc. The crumbler basket has a reel with numerous blades for breaking up dirt and sod clods into smaller sizes, chopping up the remaining debris on the top of the soil, smoothing out ridges, and slightly packing the field.
A shank assembly typically includes a spring to provide an initial preset force in order to minimize any movement of the shank as it is used in the field. If the load force acting against the shank overcomes the spring force, for example the shank encounters a rock or hard soil, the shank may pivot rearwardly, i.e., trip, to clear the obstruction. The horizontal load force which induces tripping is commonly referred to as the trip force. Thereby, the trip load may be measured as the horizontal force that acts against the sweep located at the bottom end of the shank. In some circumstances, a higher trip force may result in greater stabilization of the agricultural implement and a more level seedbed. For example, it may be advantageous to have a higher trip force when operating at greater speeds or in harder soil conditions. However, the greater trip force may not be desirable in other conditions, such as in soft soil conditions, as it could lead to increased wear on the agricultural implement.
A farmer may wish to operate a field cultivator in numerous different terrains and field conditions, including various soil types and soil conditions. To augment farming efficiency, a farmer may want to cultivate a greater number of acres in the same amount of time with one field cultivator. Thereby, to increase productivity, a shank assembly of a field cultivator may need to be operated in multiple field types and conditions. Some shank assemblies may not be capable of operating effectively in several different terrains and/or field conditions. For instance, in a harder soil condition, a shank assembly with a lessor spring rate may cause the depth of the field cultivator to undesirably vary. Thereby, a farmer may not be able to use one type of field cultivator, which has a particular set of shank assemblies, for multiple fields.
What is needed in the art is a tillage implement that can efficiently and aptly accommodate different terrain and field conditions.